Uncheck Parent Nodes When a Child Node Is Unchecked

To uncheck parent Nodes when any child Node has been unchecked, traverse from the child Node upward toward the root Node, unchecking Nodes as you go. The example below extracts the current Node (the child Node) and if it is unchecked, walks back through the Node hierarchy moving from parent to parent. Also note the condition of the while() loop. The condition checks that the parent has a set_checked function. If set_checked is undefined, we are at the root Node (the treeview itself does not have a set_checked function).

function clientNodeChecked(sender, eventArgs) {
    var node = eventArgs.get_node();
    if (!node.get_checked()) {
        while (node.get_parent().set_checked != null) {
            node.get_parent().set_checked(false);
            node = node.get_parent();
        }
    }
}

<telerik:RadTreeView RenderMode="Lightweight" ID="RadTreeView1" runat="server" CheckBoxes="True" OnClientNodeChecked="clientNodeChecked">
</telerik:RadTreeView>